Drawing instrument.



No. 685,383. Patented Oct. 29. l90l.

H. M. LANE.

DRAWING INSTRUMENT.

(Application filed. Oct. 16, 1900.)

(No Model.)

y V v q a K UNITED STATES PATENT OFFICE.

HENRY M. LANE, OF SCRANTON, PENNSYLVANIA.

DRAWING INSTRUMENT.

SPECIFICATION formingpart of Letters Patent No. 685,383, dated October29, 1901.

Application filed October 16, 190Q.- Serial No. 33,266. (No model.)

To all whom it may concern:

Be it known that I, HENRY M. LANE, a citizen of the United States,residing at Scranton, in the county of Lackawanna and State ofPennsylvania, have invented a new and useful ImprovementinDrawinglnstruments, of which the followingis a specification.

This invention relates in general to compasses or dividers fordraftsmen, and has particular'reference to the joint at the head of theinstrument.

One object of the invention is to provide a joint which is capable ofthe most accurate adjustment even after it has been long in use andwhich will maintain such adjustment perfectly.

A further object is to provide a structure which will relieve the yokeof all undue strain to which it is subjected in instruments heretoforeemployed.

'These objects I accomplish in the manner illustrated in theaccompanying drawings, in which Figure 1 shows an edge view of a pair ofcompasses having myimproved joint applied thereto. Fig. 2 is a sideelevation of the same. Fig. 3 is an enlarged sectional view takenthrough the center of the instrument. Fig. 4 shows the hinge-bolt andnut upon which are formed the cones, as will be hereinafter described;and Figs. 5 and 6 show modified forms of the bolt and nut.

Similar reference characters designate corresponding parts throughoutthe several views of the drawings, I

One great defect of the instruments of this, character which are ingeneral use lies in their lack of perfect adjusting facilities for thehead. The cones are formed on the inner ends of adjusting-screws whichextend into corresponding cups formed in the outer faces of thehinge-pieces. The cone-screws are threaded on their outsides, and whenonce adjusted they are held in place by looking set-screws. The threadsare so delicate, however, that the set-screws dent or mash into thesame. When the instrment is first assembled, it is properly adjusted andthe set-screws are tightened, which, as above described, dent or mashthe threads on the cone-screws. If new it becomes necessary to tightenthe adjustment of the head, a setscrew is loosened and the correspondingconescrew is slightly turned. This will have the desired effect; butwhen the set-screwis tightened its end will sink into the dent ordepression previously formed, which will draw the cone-screw back to itsformer position, and the adjustment is again too loose. In order totighten the instrument at all, therefore, it is necessary to turn thecone set-screw some distance, which will probably result in 'making thejoint too tight. As will be seen,

I have bya very simple device entirely overcome this serious defect.

The construction above described has no means for holding the cones totheir places except the arms of the yoke, and these are so long and thestrain upon them is necessarily so great that they are oftentimes bentoutwardly. 'As soon as this occurs the yoke is so much weakened that theinstrument can never be kept in adjustment, and so becomes almostworthless. My invention overcomes this defectalso by relieving the yokeof all undue strain. i

Referring now to the drawings, 1 and 2 are the legsof the instrument,which are of wellknown construction,except that at their hinge lendsthey are perforated, the perforations registering, so that thehinge-bolt 3 may pass therethrough. The hinge portions of the legs areseparated by the usual washer 4. the yoke, which embraces th'ehinge endof the legs and which is perforated to accommodate the hinge-bolt 3, itsnut 6, the handle 7, and the set-screws 8 and 9. All of theseperforations are threaded except the one for the nut 6, which is leftplain for a purpose hereinafter stated. The head of the hingebolt is'threaded, so that it may be screwed into its perforation in one arm ofthe yoke, with its stem projecting through the perfo-' rations in thehinge ends of the legs and into the unthreaded perforation in theopposite arm of the yoke. The stem is also threaded for a part of itslength, and on this portion screws the nut 6. The inner faces of thehead of the hinge-bolt and of the nut are coneshaped to fitcorrespondingly=shaped cups or depressions in the outer faces of thehinge portions of the legs formed by reaming out the perforations forthe hinge-bolt. The outside of the nut 6 is turned smooth and is leftunthreaded and is made to fit loosely in the unthreaded perforation ofthe yoke. It is evident that with this structure all the delicate adjustments may be made by loosening the set-screw 9andturningthenut6.Thiswillsqueezethe cones more tightly into their cups or loosen the sameif the nut is turned in the opposite direct-ion; but the strain issustained entirely by the hinge-bolt. Furthermore, the nut beingunthreaded, the set-screw 9 may be tightened at any position about thesame, as there can be no dents or depressions formed in the latter tointerfere with the proper action of the screw. This manner of adjustingthe tension may be followed exclusively until the bolt-head cone and itscup become so much worn that the legs are badly out of center with theyoke, when the set-screws 8 and 9 may be loosened and the bolt screwedfarther into the yoke. In this manner the legs and the yoke may bebrought into correct alinement, after which the adjustment may be madefrom the nut, as before.

From this description it will be seen that I have provided an adjustingmeans which is simple in its construction and operation, which iscapable of looking after the most delicate changes have been madewithout destroying the adjustment, which is adapted to set theinstrument into perfect alinement after it has become excessively worn,and which entirely relieves the yoke from strains due to the adjustment.

It is evident that my broad invention may be embodied in differentforms. For example, in Fig. 5 I have shown a hinge-bolt having a plainhead, while the nut for the same is threaded. \Vhen this form of boltand nut is employed, that arm of the yoke 5 which receives the nut has athreaded hole, while the hole in the opposite arm is left plain. In Fig.6 Ihave illustrated a form in which both the head and the nut are leftplain. When these are used, the holesin both of the arms of the yoke arealso left unthreaded.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In an instrument of the character described,a pair of legs hingedtogether, the hinged portions of the same having perforations which areprovided with cup-shaped countersinks, a yoke embracing the hinged endof the legs and having a threaded and an unthreaded perforationregistering with the perforations in the legs,a bolt passing throughsaid perforations and having a cone-shaped head and nut, one of which isscrew-threaded to fit the threaded perforations in the yoke whereby thelegs and yoke may be relatively adjusted, and the other unthreaded tofit the unthreaded perforation in the yoke, and a setscrew passingthrough the yoke and engaging the unthreaded part of the bolt wherebythe relative adjustment of the legs may be maintained.

2. In an instrument of the character described, a pair of legs hingedtogether, a yoke embracing the hinged portion of the legs and having athreaded and an unthreaded perforation, a hinge-bolt having a threadedhead which screws into the threaded perforation of the yoke, and a nutfitting loosely in the unthreaded perforation of the yoke and screwingon the stem of the bolt.

3. In an instrument of the character described, a pair of legs hingedtogether, a yoke embracing the hinged portion of the legs and havingathreaded and an unthreaded perforation, a hinge-bolt having a threadedhead which screws into the threaded perforation of the yoke, a nut,unthreaded on its outside,fitting loosely within the unthreadedperforation of the yoke and screwing on the stem of the bolt, andset-screws in the yoke for locking the bolt and the nut.

4. In an instrument of the character described, a pair of legs hingedtogether, the hinged portions of the same having registerin gperforations which are cup-shaped at their outer parts, a yoke embracingthe hinged portion of the legs and having a threaded and an unthreadedperforation, ahinge-bolt having a threaded head which screws into thethreaded perforation of the yoke, a nut fitting looselyin the unthreadedperforation of the yoke and screwing on the stem of the bolt, the innerends of the bolt-head and of the nut being cone-shaped, set-screws inthe yoke for locking the bolt and the nut, and a stem screwed into theyoke.

In testimony whereof I aflix my signature in the presence of twowitnesses.

II ENRY M. LANE.

Witnesses:

J. E. LOUIS, W. M. CURRY.

